1. Field of the Invention
This invention relates to a locking differential that includes a pair of coaxially-arranged axially-spaced clutch members that are connected against rotation by cooperating locking lug and slot means contained on the adjacent faces of the clutch members. In a preferred embodiment, the adjacent faces of the clutch members also contain diametrically extending cam grooves that receive a driving cross pin the ends of which are supported by a tubular sleeve that is non-rotatably mounted concentrically within the cylindrical housing of the differential.
2. Brief Description of the Prior Art
Locking differentials for automotive vehicles are well known in the patented prior art, as evidenced by the patents to Lewis No. 2,555,044, Zentmyer No. 5,413,015, and Valente Nos. 5,590,572 and 5,727,430, and Dissett No. 5,715,733.
In these known differentials, it is common to utilize a pair of annular coaxially-arranged axially-spaced clutch members arranged on opposite sides of a diametrically extending driving cross pin that extends within mating cam grooves contained in the adjacent faces of the clutch members. Spring means normally bias the clutch members apart, and a locking pin extends axially from one face into a recess contained in the adjacent face of the other clutch member, thereby to prevent relative rotational movement between the clutch members. The locking pins are generally separate components, used in connection with a plurality of biasing springs and spacer disks or plugs, thereby causing assembly of the differential to be relatively labor intensive and manually difficult.
In the differential conversion market, it is common to retrofit one type of differential into the housing of another type of differential. For example, in certain automotive environments such as in high-performance all terrain four-wheel drive vehicles, it is desirable to substitute within a given casing a fully locking type differential for a limited slip differential. In one specific instance, it may be desired to retrofit within the differential housing of a limited slip differential mechanism of the fully locking type.
Accordingly, a primary object of the present invention is to provide a fully locking differential mechanism that is adapted to be retrofit within the housing of another type of differential, use being made of a mounting sleeve adapted for insertion and non-rotatable connection within the housing, which mounting sleeve carries the diametrically arranged cross pin the differential mechanism.
According to another object of the invention, the locking means of preventing relative rotation between the clutch members arranged on opposite sides of the cross pin comprises locking lugs that extend axially from one face of one clutch member into corresponding locking slots contained in the adjacent face of the other clutch member. In one embodiment, each clutch member contains a single locking lug and a single diametrically arranged locking slot operable to cooperate with a corresponding locking slot and locking lug on the adjacent face of the other clutch member. In a second embodiment, one clutch member carries two diametrically arranged locking lugs, and the other clutch member carries a corresponding pair of locking slots.
Owing to the use of the locking lugs and slots, the use of dowel-type locking pins and the associated machining of the holes therefore are eliminated, thereby reducing the number of parts and machining steps, whereby the overall cost of the clutch members is reduced. The resulting locking lug and slot design is more robust and durable, than the prior weak dowel pins, which often fail through use. Another advantage of the invention is that by the use of the locking lugs and slots; more space is provided for accommodating four biasing springs, rather than the two springs of the prior art. In the embodiment wherein each clutch member carries at least one locking lug and at least one locking slot, the further advantage is achieved that a pair of identical clutch members can serve as the clutch members of the differential, whereby the inventory of the types of clutch members required for production is reduced to one.